Hi,
I’m using some python code on a ConnectPort X to read some modbus devices using a Zigbee -> RS-485 adapter.
I’d like to read some BACNet devices in a similar manner. I’ve taken a look at the BACpypes python library and all the examples are using IP. I couldn’t find any examples that used BACnet MS/TP and RS-485.
Has anyone done anything like this?
True BACnet MS/TP is a timing nightmare (per some Digi embedded customers who use a Digi Connect ME for BACnet MS/TP). Packets are expected to move with millisecond accuracy - which won’t survive normal Zigbee. You would not likely be able to just use simple ‘encapsulation’ to a BACnet RS-485 device which was not aware of the ZigBee link.
However, bacnet.org has created a BACnet spec for how to encapsulate BACnet packets over ZigBee. The catch is the remote node would be expecting this special form, not MS/TP.
Thanks Lynn!
On to plan B… I’ve been working on getting an ethernet connection to the BACnet controller. It looks like that will be the way to go in the long run.